CALIFORNIA - A MAN in a ski mask waved an American flag and a handgun on a freeway overpass for about three hours on Monday morning, forcing a massive traffic shutdown before he surrendered.

Police say crisis negotiators coaxed Edward Van Tassel, 28, to give up west of downtown Santa Barbara on Highway 101, a major route along the California coast. Traffic was jammed at least five kilometres in each direction.

After dropping his weapon, Van Tassel asked for a Barack Obama campaign sign, which authorities delivered to him using a bomb squad robot, police said.

The man attached the sign and the flag to the overpass and later walked backward to officers, who took him into custody.

No shots were fired and police said the man's gun turned out to be unloaded.

Van Tassel, an Iraq veteran from Santa Barbara, was taken into custody without incident, said police Sgt Lorenzo Duarte.

The sergeant said Van Tassel had been in the Army but he did not have any details of his Iraq service.

As for the man's motive, Sgt Duarte said, 'The reason appears to be anti-war, but I don't know the specifics.'

Police were continuing to investigate a duffel bag and the man's car at the scene but 'we have no credible threats or any threats of explosives', police Sgt Jim Pfleging said.

Sgt Pfleging said Van Tassel will receive a mental health evaluation.

Telephone directory assistance had no listing for Van Tassel.

Van Tassel was booked for investigation of possession of a concealed firearm, possession of an illegal weapon, resisting arrest, brandishing a weapon, disturbing the peace, wearing a mask for the purpose of committing a crime and allowing an unlicensed driver to drive.

Police also arrested a second man, Aaron Levy, 33. Investigators allege Levy drove Van Tassel to the scene and 'was aware of what was going to happen,' Sgt Duarte said.

Levy was booked for investigation of conspiracy, possession of a dangerous weapon and driving on a suspended license. -- AP